Touch controlled circuit



United States Patent Ofitice 3,056,907 Patented Oct. 2, 1962 3,056,907 TOUCH CONTRULLED CIRCUIT Raphael J. Costanzo, Bridgeport, Conn, assignor to Harvey Hubbell, Incorporated, Bridgeport, Conn, a corporation of Connecticut Filed Oct. 16, 1958, Ser. No. 767,661 3 Claims. (Cl. 317-149) This invention relates to a touch-controlled circuit, that is, a circuit in which the operator may control the operation of the circuit by merely touching one or more elements, without requiring the throwing of a switch or the like, and has for an object to provide an improved and simplified arrangement for controlling a load circuit and one which may be readily adjusted for more eflfective operation under different conditions, and one which will provide more positive action under a greater magnitude of changing conditions.

Another object is to provide a touch-controlled circuit, including a relay controlling the load circuit in which improved means is provided for operating the relay which will effect a more positive and reliable operation or" this relay.

Another object is to provide a control of this type which has a high degree of safety and provides a system which lends itself extremely well to use in explosionproof areas, and makes it possible to eliminate the use of all the bulky and complicated switches in sealed enclosures now presently on the market to protect against these conditions.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modiications within the scope of the invention.

In this drawing:

FIG. 1 is a diagrammatic view of a touch circuit embodying this invention;

FIGS. 2, 3 and 4 are plan views of diiierent types of touch elements which may be employed in this circuit;

FIG. 5 is a section of the preferred type of latching type relay which may be used in this circuit, showing the load control switch in the open position, and

FIG. 6 is a similar section showing the control switch closed.

The drawing (FIG. 1) indicates the control for a load circuit such, for example, as a lighting circuit, as in house lighting for a room or the like, in which the operator by merely touching a plate or strip of metal may put the lights on or OE. With the latching type relay for controlling the load circuit, if the lights are on, then he can put them 0E by touching this plate or strip, and if the lights are off he can put them on by merely touching this plate or strip. It will, however, be understood that this touch circuit is not limited for use for controlling a lighting circuit, but may be used for other applications where a touch control may be desired, although it is particularly adapted and efiective for use in controlling a lighting circuit.

The circuit as shown in FIG. 1 includes means for connecting it to the usual A.C. supply indicated at 10, which may be the usual 110 to 115 volt circuit used for house lighting systems. The load indicated by the circle 11 may be one or more lamps controlled by a mechanical latching relay 12 including a control switch 13 for controlling the circuit represented by the conductor connections 14 and 15 connected to the leads 16 and 17 from the AC. supply 10. By latching relay is meant a relay in which, when the operative coil or winding 18 of the relay is energized Whenthe switch 13 is either open or closed, it will shift it to the other position. Thus, if the switch 13 is open when the coil 18 is energized it will close this switch and it will remain closed and therefore put the lights 11 on or operate the load, and it will remain closed until the coil or winding 18 is again energized, when the switch 13 will open and remain open to put the lights out or stop operation of the load until the coil is again energized, and so on. The operation of the switch is effected by operation of the armature 19 of the relay through the core 20 energized by the Winding 18 operating through suitable latch mechanism 21, which as indicated above, on energization of winding 18 will shift the movable contact of the switch 13 from either the closed to the open position or vice versa, depending on its position when the coil or winding 18 is energized.

Connected across this operative coil or winding 18 of the relay is a rectifier or diode 22 in series with a resistor 23. Rectifier 22 is preferably a silicon rectifier, as this has been found to be more reliable in operation in this combination and provide more effective and satisfactory results. The operative coil 18 of the relay is connected in series with the AC. supply 10 and the cathode and anode of a cold cathode electric discharge tube such, for example, as a thyratron 24;. The grid or control electrode 25 of this tube is connected through a high resistance 26, preferably a high adjustable resist ance, such, for example, as a potentiometer, with a touch element or area 27 through the lead connection 28, the resistance 26 being thus in series with the grid and touch element or area. This touch element as shown in FIG. 1 may be a substantially rectangular plate, or such a rectangular plate may be elongated to the form of a flat tape or strip 29, or this touch element or area could comprise two of these tapes or strips 29 and 30 separated a short distance so that they are insulated from each other but are placed side by side and closely adjacent. In this arrangement one of these strips, in the present case the strip 29, is connected to the grid 25, while the other tape or strip 30 is gounded, as indicated at 31; or, if preferred, the two strips or tapes 32 and 33 could be arranged in the folded arrangement of FIG. 4, of the size of a rectangular plate, the element 32 corresponding to the tape or strip 29 and the element 33 corresponding to the tape or strip 30, the element 32 being connected to the grid 25 by the lead 28 and the element 33 being grounded at 34. Each element as shown comprises branches 35 and 36 respectively arranged in alternate arrangement side by side and close together but insulated from each other the same as in FIG. 3.

The operation is as follows:

The electric discharge device or tube 24 is so designed that it will not fire under ordinary conditions with the alternating current voltage supplied from the supply 10. That is, the potential supplied to the cathode and anode or plate of this tube by a leakage from the cathode builds up a negative voltage or potential on the grid 25 which prevents the tube from firing under ordinary conditions. If the operator touches one of the touch elements, that is, either the plate 27, elongated plate or strip 29, the two strips 29 and 39, or the two elements 32 and 33, depending on which type of touch element is used, and connected to the grid 25, this discharges the grid 25 or makes it more positive and reduces its negative voltage below the firing voltage of the tube, and it will fire, energizing the coil 18 of the relay 12, and will operate the switch 13. As indicated above, instead of the touch element being a relatively small plate 27, this plate may be elongated into a narrow strip or tape 29 extending around the moulding, for example, in a room; or for long strips, two or more may be used close together, as

shown in FIG. 3, but in this case one of them should be grounded for more reliable operation, but they are so narrow and arranged so close together that it is practically impossible for the operator to touch one without touching the other, and that, of course, grounds the grid 25 of the tube 24, which causes it to fire and operate the relay. The same is true of the folded-up arrangement of the contact strips as shown in FIG. 4.

Other types of rectifiers or diodes 22. could be used, but the silicon rectifier is preferred as it has better operating characteristics and will carry larger current surges for comparative size. This rectifier is used acoss the coil or winding 18 because it causes the current to persist longer when the tube 24 is fired, preventing chatter or continuous off and on operation of the relay, and thus persists long enough to operate the relay satisfactorily. The potentiometer or the adjustable resistance 26 between the grid and the touch element adds a sui ciently high resistance so there is no danger of injurious voltage on the touch element, and it also permits adjustment of the resistance to stabilize the different touch elements used in different set-ups, or to compensate or effect the most effectiveoperation under varying conditions encountered in different applications. By this adjustable resistor the touch strips and the controls can be arranged to control the firing of the tube, and therefore operation of the relay, to permit operation by touch at any one point or location along the strip or strips, by increasing or decreasing the resistance from the grid to the touch area.

The characteristics of the various elements will of course be determined for the conditions or set-ups involved. Thus, for example, in an ordinary house lighting system the relay 12 could be of 1380 ohms resistance, and the resistor or potentiometer 26 could be from 5 to megohms, or it could be a fixed resistor of the proper characteristics employed after the proper or required resistance has been determined for the set-up or conditions in which it is installed. This could be what might be called an adjustable or variable fixed resistor. That is, instead of having the resistor itself adjustable to determine the proper amount for a given touch field, a series of different fixed resistors of different values may be tried until the proper one for the field is indicated. This would prevent someone, as a child, for instance, from changing the proper resistance in any given set-up after it had been determined, and thus interfering with the proper functioning of the installation involved.

By varying the resistance between the grid and the touch area it is possible to control the length of such area that will be most effective for any given set-up or installation. The touch area can be so constructed as to be a solid length, a split length or a laminated length, with one split area connected to ground. This enables the obtaining of more positive action under a greater magnitude of changing conditions.

By use of the rectifier across the coil of the mechanical latching relay it is possible to maintain a much more stable unidirectional pulse, which gives more positive control. This is accomplished with this arrangement by using only three components. Also by extending the tape or touch area around a room or predetermined area it makes it possible to obtain infinite switchings along the length of the tape. Also, due to the minute potential which is on the touch area, this type of system lends itself extremely well for use in explosion-proof areas, thus eliminating the use of all the bulky and complicated switches in sealed enclosures now presently on the market for use to protect against these conditions. This touch area can be a length of wire, metallic tapes, or any wire or tape of conducting material, such, for example, as copper or aluminum or suitable metal alloys. This system using the rectifier and resistor across the operative coil or winding of the relay eliminates the possibility of a skip operation in the latching relay and gives a more uniform contact operation. In other words, it increases the length of time of the unidirectional pulse which results in more positive action. It does this because, as the grid is triggered or allowed to become more positive, and allows the electrons to flow from the cathode to the plate, this initial pulse does not have a wave form which will consistently trigger a latching relay. By the insertion of a diode across the relay, a pure unidirectional pulse now becomes apparent. This is due to the low forward current-carrying characteristics of the diode and its extremely high reverse current-carrying ability plus its high peak inverse voltage characteristics.

As above suggested, the use of this diode and resistor for bypassing the operative winding of a relay is not limited to use in latching type relays, as it could be used for counting or sorting operations by use in conjunction with conventional relays where such operation is desired.

The significant points or improvements in the present purpose or set-up are the diode connected across the operative coil of the relay, the varying resistor placed be tween the grid and the touch area (this, by the way, being very important in this combination), and also the improved means of accomplishing the operation of the touch area by connecting one side to the grid through this resistor and one side to the ground, and therefore grounding the grid by the operator touching the two parts of the split area.

By using the variable resistor between the grid and the touch area it is possible to control Varying lengths of touch or control areas. As suggested above, a resistor of the fixed or variable type may be used, the variable type being used where it is desired to vary or control the length, width or distance of the touch areas, but if the length of the touch area has been predetermined for the given set-up or application involved, then a fixed resistor of the proper value and designed for this particular length can be used to prevent the possibility of anyone changing the resistance after the installation has been made, and thus interfere with proper functioning of the installation involved. This, however, is in effect adjustable resistor application.

As previously suggested, this control is well adapted for use in explosive proof areas, as the touch area or elements may be within this area and there is no arcing or significant voltage to cause explosive reaction, and the relay may be located in any remote location outside the explosive proof area.

Having thus set forth the nature of my invention, I claim:

1. In a touch controlled circuit, a cold cathode electric discharge tube including a cathode, an anode and a control grid, means for connecting the cathode and anode "to an alternating current supply, a load control relay including an operative winding connected in series with the said supply, the cathode and the anode, a rectifier connected across said winding, a touch element comprising a pair of separated conductors placed side by side and closely adjacent whereby both may be simultaneously touched by a single finger of a user, means connecting one of said conductors to the grid, and means grounding the other conductor, the discharge tube having characteristics whereby it will remain non-conductive under the voltage of the source of alternating current until the charge on the control grid is increased positively by grounding the touch element conductor connected therewith and then will fire with a pulse discharge through the relay winding and rectifier.

2. In a touch controlled circuit, a cold cathode electric discharge tube including a cathode, an anode and a control grid, means for connecting the cathode and anode to an alternating current supply, a load control relay in. cluding an operative winding connected in series with the said supply, the cathode and the anode, a rectifier connected across said winding, a touch element comprising a pair of separated narrow elongated conductor tapes arranged side by side and closely adjacent whereby a user automatically touches both simultaneously, means connecting one of said tapes to the grid, a potentiometer connected in series with said tape and the grid, and means grounding the other tape, the discharge tube having characteristics whereby it will remain non-conductive under the voltage of the source of alternating current until the charge on the control grid is increased positively by grounding the touch element conductor tape connected therewith and then will fire with a pulse discharge through the relay winding and rectifier.

3. In a touch controlled circuit, a cold cathode electric discharge tube including a cathode, an anode and a control grid, means for connecting the cathode and anode to a source of alternating current, a lighting circuit, a latch type relay including a switch controlling said lighting circuit and an operative winding controlling said switch and connected in series with said source and the cathode and anode, a rectifier connected across the said winding, a touch element comprising a pair of separated narrow elongated conductor strips placed side by side and closely adjacent whereby both are automatically References Cited in the file of this patent UNITED STATES PATENTS 1,840,055 Rentschler Ian. 5, 1932 2,062,269 Knowles Nov. 24, 1936 2,810,066 Green Oct. 15, 1957 2,848,659 Cutler Aug. 19, 1958 2,870,329 Aubert Jan. 20, 1959 2,896,131 Schumann July 21, 1959 OTHER REFERENCES Parrish: Electronic Design, November 15, 1956; pages 22-25.

Sandretto: Radio-Electronics, September 1957; pages 61-63. 

